Man I just put a small block, like the size of VHS tape. so a 1x3 5-6 inches long. Yesterday I didnt even use a block of wood. Saftey wise just make sure your on level ground and I would not worry about anything. I got this lift method from a search where I think SPAZZ did this. Its just quicker and easier. Under the tank you will see 4 or 5 indentions the block of wood was just used to disperse the weight of the VX further than the 4inch disc of the jack. I hope you got a jack large enough.

I ask her this weekend.